Not applicable.
The present invention relates to a segmented roll comprised of a plurality of end-to-end mounted roll segments, each adapted to rotate on bearings supported on a separate support shaft.
When desired, the bow of such a segmented roll can be changed by adjusting the position and/or distance of the support points of the individual roll segments in regard to their mounting frame, thus making the roll extremely suitable for use, e.g., as a spreader roll in conjunction with the handling of a web-like continuous sheet of material. The segmented roll is also suited for use, e.g., as a guide roll for a paper web or as a pressure roll in winding.
In conventional segmented roll constructions, each of the roll segments is generally journaled at its both ends on bearings which are supported on the segmented roll mounting frame or similar support framework. Frequently, two adjacent roll segments share one bearing unit. Then, removal of one roll segment from the central area of this kind of segmented roll may be difficult, because the segmented roll must be disassembled starting from one end in order to reach the roll segment to be replaced at the central area of the segmented roll.
From FI laid-open publication no. 62514 is known a spreader roll of the above-described type, wherein the respective abutting stub shafts of adjacent roll segments are adapted to be supported on a two-part support bearing block that determines the roll bow. Thus, each stub shaft is provided with a separate support bearing that is designed to function as a pivotal bearing point. The pivotal bearing points of the abutting stub shafts are adapted in close proximity to each other on the different sides of the support bearing, whereby each support bearing unit supports one of the adjacent pivotal bearing points. This kind of a two-part support bearing block makes it possible to dismount and replace separate roll segments without the need for complete disassembly of the entire spreader roll. On the other hand, such an arrangement places two bowing points at a small distance from each other thus causing nonuniform bowing of the roll. As the bowing point is not exactly at the mating point of the abutting roll segments, but rather, displaced by a small distance therefrom, the bend of the roll tends to lift up the end of the roll segment and thus makes the roll rotate bowed into a toothed shape. Hence, the correct geometry of roll bow is not attained which causes problems in controlling the web travel.
It is an object of the invention to provide a novel type of segmented roll in which all separate roll segments are dismountable and replaceable without the need for complete disassembly of the entire segmented roll and which segmented roll is capable of assuming a smooth bow.
The segmented roll according to the invention has coupling means adapted to both axial end surfaces of the support shafts of its roll segments, said coupling means serving to disengageably connect two adjacent roll segments to each other. The support shaft contains at least two parts such that changing the mutual disposition of said parts makes it possible to alter the axial length of the support shaft.
Advantageously, the coupling means on the support shaft end surfaces are such that allow a coupling to be established between two adjacent roll segments, the coupling being capable of accommodating an inclination between the longitudinal axes of the adjacent roll segments. The coupling means may contain a projection or the like on the end surface of the first roll segment and a mating recess on the end surface of the second roll segment. The projection can be formed, e.g., by an annular flange projection made to the end surface of the support shaft with a shape allowing limited rotation and inclination of the projection in a concentric annular recess made to the end surface of the adjacent roll segments when the adjacent roll segments are coupled to each other. Alternatively, one of the mating coupling surfaces may be formed by a concave hemispherical surface, whereby the mating end surface is formed by a convex hemispherical surface. In this arrangement for bowing the segmented roll to a desired curvedness, only one of the mating ends of the adjacent roll segments needs to be directly supported to the mounting frame, while support for the other end is provided by the end of the adjacent roll segment.
The support shaft of the roll segment is comprised of two parts adapted to be solidly, advantageously nonrotatably, lockable to each other with the help of a locking element. After the locking element is released, the shaft parts can be axially moved with respect to each other by a distance allowing the coupling means formed on the mating end surfaces of the abutting roll segments to be withdrawn apart from each other.
Advantageously, the first part of the support shaft includes an axial projection, most advantageously like a peg that is adapted to fit into an axial bore of the second part of the support shaft. The locking element can be a fastening member, advantageously a lock screw, placed into a radial hole made to one end of the support shaft, the tip of the locking element in its locking position being adapted to press against the outer circumference of the support shaft axial projection thus being capable of solidly locking both parts of the support shaft to each other.
Preferably, the lock screw or similar locking element also has another functional position. To this end, the length of the lock screw is advantageously made such that when the lock screw is turned away from resting against the outer circumference of the axial projection, the screw head will tuck against the inner circumference of the roll segment shell thus coupling the other part of the support shaft to follow a possible movement of the roll segment shell. The inner circumference of the roll segment shell is adavantageously provided with a recess suitable for assuring positive contact of the screw head with the roll segment shell when the roll segment is being rotated.
Advantageously, at least a portion of the axial projection part and the axial recess part connecting the abutting parts of the support shaft to each other have compatible outer and inner threads, respectively, made thereto. Thus, having first the locking means disengaged, it is possible with the help of the threaded portions to move one part of the support shaft by rotation thereof in regard to the other part in the axial direction.
Advantageously, the roll segment of the segmented roll according to the invention is comprised of an outer shell and an inner shell connected to each other by a disc portion. Both parts of the support shaft are provided with an annular recess opening toward the interior of the roll segment, said recesses being adapted to accommodate the tubular flange parts of the inner shell extending to both sides from said disc portion. Each roll segment is rotatably mounted on the support shaft preferably using two bearings, advantageously ball bearings, having their inner races fixed to the rotating inner shell of the roll segment and their outer races fixed to the inner surfaces of the outer walls of the annular recesses made to the support shaft.
Advantageously, the segmented roll comprises a plurality of roll segments having their support shafts mounted only at one end on the mounting frame of the segmented roll, complemented with one roll end segment having its both ends mounted on the mounting frame. The mounting arrangement of the support shaft end on the frame is advantageously such that allows the position on and/or distance of the roll segment end to be adjusted in regard to the mounting frame.
In a segmented roll embodiment according to the invention, it is possible to replace any single roll segment in the central area of the segmented roll without the need for complete disassembly of the entire segmented roll assembly. To this end, only one end of each roll segment is mounted on the segmented roll mounting frame, while the other end is supported on the adjacent roll segment by means of a coupling that can be disengaged through adjusting the support shaft of the roll segment to a shorter length.
As the bowing point between two adjacent roll segments is arranged to coincide with the mating plane of their ends, the segmented roll will bow evenly without any toothed jaggedness in its curvature. Hence, the segmented roll is unproblematically suited for supporting a web, for instance.